Concepts of Spin Seebeck Effect in Ferromagnetic Metals

Abstract

Spin Seebeck effect (SSE) and related spin caloritronics have attracted great interest recently. However, the definition of the SSE coefficient remains to be established, let alone a clean experiment to measure the SSE coefficient in ferromagnetic metals. The concept through a model based on the semi‐classical Botlzmann transport equation has been clarified. The model includes the vital spin‐flip process, which is frequent in metals, and points out that the length scale of SSE is much larger than the spin diffusion length. The model reveals how the spin‐flip process influences the transport equations and provides the simple relationship between the different spin‐flip relaxation times for spin‐up and ‐down electrons, which is very useful to understand the spin transport properties. This understanding allows to redefine the expression of the spin Seebeck coefficient.

Nonequilibrium Transport Properties of Magnons in Steady States in Magnetic Insulators

“…When a temperature gradient is applied and a magnon current is generated in MI, a nonequilibrium steady state is established through two types of interactions: (i) elastic scattering, which conserves the number of magnons, such as magnon-magnon interaction, and (ii) inelastic scattering, which does not conserve the number of magnons, such as magnon scattering with phonons, lattice defects, and grain boundaries. This macroscopic transport steady state can be described by the Boltzmann transport equation in the relaxation time approximation 23 :…”

Functionalized hybrid magnetic catalytic systems on micro- and nanoscale utilized in organic synthesis and degradation of dyes

“…This is the case when the measuring time is longer than the relaxation time; however, when the measurement time is shorter than the relaxation time, the nanoparticles are in a "blocked" (ferromagnetic) regime. 230,231…”

Large Improvement of Thermoelectric Performance by Magnetism in Co‐Based Full‐Heusler Alloys

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